Anti-theft device for marine propellers

Abstract

An anti-theft device, for preventing unauthorized access to the propeller retaining nut, includes two sections that fit together to form an access-preventing cap. The cap fits around an expanded rim normally found on propeller center-bodies, and the cap cannot be pulled off the propeller center-body without disengaging the two sections from one another. A tongue extending from one section is engaged by a grooved dowel going through the base portion of the second section to hold the two sections together. A key operated locking flap engages the groove in the dowel to prevent removal of the dowel without possession of the appropriate key. In a second embodiment, an adapter is placed on the propeller shaft, between the propeller and the propeller retaining nut. The access-preventing cap is of smaller dimensions than in the first embodiment and is shaped to engage the adapter.

I claim: 
     
       1. An anti-theft device for marine propellers, comprising: a first section having a first base portion and a first wall portion;   a second section having a second base portion and a second wall portion, said first section and said second section fitting together to form an access-preventing cap having a base portion and a surrounding wall extending from said base portion, said surrounding wall having a rim portion distal from said base portion, said rim portion defining a front opening, said front opening having a first diameter, said base portion and said surrounding wall defining a first cavity sized to house a diffuser portion of a marine propeller hub,   the diffuser portion being formed at least in part by an expanded portion being larger in diameter than said first diameter such that, when the diffuser portion of the marine propeller hub is housed within said first cavity, said access-preventing cap cannot be pulled off the marine propeller hub without first separating said first section from said second section,   said first base portion having a tongue extending therefrom, said tongue having a first through hole, said second base portion having a second through hole extending from an exterior surface of said second base portion, said second through hole being in registry with said first through hole when said first section and said second section are fitted together to form said access-preventing cap;   a dowel, said dowel extending through said second through hole and said first through hole to prevent said first section from being separated from said second section, when said first section and said second section are fitted together to form said access-preventing cap and said dowel is positioned to extend through both said second through hole and said first through hole; and   a key-operated lock incorporated in said first base portion, said key operated lock being selectively engageable with said dowel,   said key-operated lock preventing said dowel from being removed from said second through hole and said first through hole when said key-operated lock engages said dowel, when said dowel is positioned to extend through both said second through hole and said first through hole, and when said first section and said second section are fitted together to form said access-preventing cap.   
     
     
       2. The anti-theft device for marine propellers according to claim 1, wherein said second base portion has a second cavity having an interior, said second cavity receiving said tongue when said first section and said second section are fitted together to form said access-preventing cap, said second through hole at least extending between said exterior surface of said second base portion and said interior of said second cavity. 
     
     
       3. The anti-theft device for marine propellers according to claim 1, wherein said dowel has a groove and said key-operated lock has a locking flap which is selectively engageable with said groove to secure said dowel in place within said first through hole and said second through hole. 
     
     
       4. The anti-theft device for marine propellers according to claim 1, further including a flexible tethering means connecting said dowel to one of said first section and said second section. 
     
     
       5. An anti-theft device for marine propellers, comprising: an adapter having a peripheral wall and an adapter base, said adapter base having a through hole to allow passage of a propeller shaft therethrough, said peripheral wall having at least one flange extending radially therefrom;   a first section having a first base portion and a first wall portion;   a second section having a second base portion and a second wall portion, said first section and said second section fitting together to form an access-preventing cap having a base portion and a surrounding wall extending from said base portion, said surrounding wall having a rim portion distal from said base portion, said rim portion defining a front opening, said front opening having a first diameter, said base portion and said surrounding wall defining a cavity sized to house at least said flange,   said flange being larger in diameter than said first diameter such that, when said flange is housed within said cavity, said access-preventing cap cannot be pulled away from said adapter without first separating said first section from said second section,   said first base portion having a tongue extending therefrom, said tongue having a first through hole, said second base portion having a second through hole, said second through hole being in registry with said first through hole when said first section and said second section are fitted together to form said access-preventing cap;   a dowel, said dowel extending through said second through hole and said first through hole to prevent said first section from being separated from said second section, when said first section and said second section are fitted together to form said access-preventing cap and said dowel is positioned to extend through both said second through hole and said first through hole; and   a key-operated lock incorporated in said first base portion, said key-operated lock being selectively engageable with said dowel,   said key-operated lock preventing said dowel from being removed from said second through hole and said first through hole when said key-operated lock engages said dowel with said dowel positioned to extend through both said second through hole and said first through hole and with said first section and said second section fitted together to form said access-preventing cap,   whereby when said adapter is mounted on the propeller shaft between a propeller hub and a propeller retaining nut, said key-operated lock is engaged to said dowel, said dowel is positioned to extend through both said second through hole and said first through hole, and said first section and said second section are fitted together to form said access-preventing cap, unauthorized access to the propeller retaining nut is prevented.   
     
     
       6. The anti-theft device for marine propellers according to claim 5, wherein said dowel has a groove and said key-operated lock has a locking flap which is selectively engageable with said groove to secure said dowel in place within said first through hole and said second through hole. 
     
     
       7. The anti-theft device for marine propellers according to claim 5, further including a flexible tethering means connecting said dowel to one of said first section and said second section.